No. For the 3D Bluray and the DVD versions it takes 2 discs to fit the entire extended movie. They probably compressed the regular blu-ray just a bit to fit the entire movie on one disc.
So for the DVDs you have 2 Movie Discs and then the special features are spread out onto three discs since 3 hours of footage is about the limit for a DVD. With 9 hours of 'Bonus Content' it takes 3 discs compared to the two blu-rays. So you have two extra discs that the non-3D Bluray doesn't need.
Fun Fact: For The Lord of the Rings Extended Editions, both the Bluray and Dvd versions came with the special features on DVDs, so the amount of discs were the same.